Apparatus for comminuting refuse

ABSTRACT

An apparatus for comminuting refuse comprises a feed hopper leading to a housing in which one or more rotating knives cooperate with one or more fixed cutting strips. One or more openings in the bottom of the housing serve to remove the comminuted refuse formed. Each rotating knife is characterized by one or more tips which lies or lie forward, i.e., in the direction of rotation of the knife, and by cutting edges which run backwards along a cylindrical surface towards the back of the knife. The back of the knife is used to mount the knife on an axle using a knife support.

United States Patent Schweigert Aug. 29, 1972 [54] APPARATUS FOR COMMINUTING 2,562,282 7/1951 Nickle et al. ..241/ 141 REFUSE 3,353,754 11/1967 Heijnis et a1 ..241/22O X 3,360,204 12/1967 Merges et al. ..24l/189 X [72] Invent 'g schwe'gm Osnabmk 3,510,077 5/1970 Priscu ..241/241' 3,578,252 5/1971 Brewer ..241/22O X [73] Assignee: Bruno Vogel, Basel, Switzerland 22 Filed: July 1 1970 Primary ExaminerR0bert L. Spruill Att0rneyWender0th, Lind and Ponack [2 1] Appl. No; 51,415

' [57] ABSTRACT [30] Foreign Application Priority Data July 4, 1969 Switzerland ..10293/69 An apparatus for comminuting refuse comprises a feed hopper leading to a housing in which one or more 52 us. c1. ..241/142, 146/184, 241/221, rotating knives with One fixed 241/224 cutting strips. One or more openings in the bottom of 51 Int. Cl. ..B02 18/06, B02C 18/40 the using Serve to remve the cmhmihuted refuse [58] Field of Search .241/99, 141, 142, formed- Each rotating knife is Characterized by one or 22 224, 238, 239,241 247, more tips which lies or lie forward, i.e., in the 255,277,286, 189,291, 293, 294; direction of rotation of the knife, and by cutting edges 146/133, 184 which run backwards along a cylindrical surface towards the back of the knife. The back of the knife is [56] References Cit d used to mount the knife on an axle using a knife suport. UNITED STATES PATENTS p 1,404,981 l/1922 Letz ..241/293 X 1,672,544 6/1928 Rynders ..241/221 X 8 Claims, 10 Drawing Figures 2,216,612 10/1940 Dimm et a1. ..241/24l X Patented Au .29, 1972 3, 687,378

I 4 Sheets-Sheet 2' v INVENTOR I LUITPOLD SCI-M/EIGERT mc/c ATTORNEYS I Pate nt ed Aug. 29, 1972 4 Sheets-Sheet s FlG.3b I

mvz-zw'ronv LUITPOLD SCHWEIGERT ATTORNEYS Patented Aug. 29, 1972 4 Sheets-Sheet 4 Y1 Q 3 LL.

Q at g INVENTOR LUITPOLDI 'SCHWEIGERT ATTORNEYS APPARATUS FOR COMMINUTING REFUSE In all civilized countries the steadily increasing quantity of refuse, especially the so-called bulky refuse in the form of relatively bulky containers of metal, glass, plastics, cardboard etc., presents considerable problems. The problem of refuse removal or volume- I munities, does indeed seem to be an ideal solution;

however, combustion plant is very expensive, and the energy produced is relatively small in comparison with the great expense in collecting the refuse, storing it and feeding it to the furnace. Experiments have shown that comminuted refuse in granulated form permits a measured feed of refuse to the combustion furnace and increased energy production.

It is already known that comminution is vitally necessary not only in the case of refuse which is to be burned, but also for refuse which is to be dumped; and hence attempts have been made to comminute the refuse using noisy and costly hammer mills. Such equipment is preferably in the form of large-scale plant, and is not within the means of small communities, particularly as the considerable costs of removal of the refuse itself have to be deducted from the revenue ob-' tained. So development lies in the direction of smaller and cheaper machines for comminution of refuse on the spot where it is produced day-by-day, viz in households, restaurants and similar large scale kitchens and in business and industrial establishments.

When it is comminuted on the spot, there is a great saving of storage space, refuse-containers and transport vehicles; and dumping immediately on removalcan be 7 performed.

The significance of on-the-spot comminution is explained by the fact that with a bulk-reduction of up to 90 percent, storage costs, storage space and transport costs are also reduced.

A bulk-reduction of part of the refuse has already been achieved by sorting out the compressible parts such as metal cans and possibly glass containers, and compressing or smashing in a press. The remaining components of the refuse, particularly plastics containers and cartons, milk-cartons of paper etc., cannot be treated in such tincanor glass-presses, since they more or less recover their shape after pressing. Sorting the refuse into various categories cannot be undertaken either in private households or in industrial premises. Hence there arises the vital necessity to create an apparatus which is capable of comminuting all forms of refuse at the same time, and which takes up the minimum of space, but which also works quietly and is favorably priced.

It has now been attempted to carry out the comminution with contrary acting cutting rollers similar to machines for destroying official documents. However, in order that the cutting rollers shall be able to engage bulky material particularly containers of metal and plastics material, the cutting rollers were provided with pick-up knives, whose tips pierce hollow articles and force them on to the rollers. Hereby arises the considerable disadvantage that the cutting rollers must be mounted in an exactly fitting mutual relationship and in their alignment on the axle must be kept apart by exact spacing rings. Moreover, to prevent the blocking of the space between the rollers, a special device for the continuous clearing of this space must be provided. Because material in strip form, either added as such or cut into strips in the machine, bunches up inside the channel between the large pickup knives to several thicknesses, a higher power requirement is necessary for the cutting. Even slight inexactitudes in the distance between the rollers can cause the material to stick fast between the rollers, and remain systematically uncut, so that the cutting capacity is further reduced and a further increased power-demand results.

Furthermore, machines are known in which a tubular housing with almost axial knife beams is provided, in which knife jaws, also mounted similarly almost axially, rotate, so that they co-operate with cutting strips, and thus disintegrate the cut material caught in the outlet openings of the tubular housing which usually has a sieve-type structure. These machines are, however, exclusively used for the disintegration of soft, semi-soft or ductile materials such as plastics, leather or rubber;

they run at relatively high speeds of rotations, make a speeds, they suffer from an enormous abrasion of the knives, and as mentioned above, do not bite on articles of large volume, but whirl these round inside the housmg.

The object of the present invention is to devise an apparatus for the comminution of refuse which eliminates or reduces the disadvantages mentioned above, works relatively quietly, and can be prepared so small and economically that it can be advantageously used even in small guest houses and family enterprises.

The apparatus according to the invention is characterized by a housing, provided with a feed hopper, a rotor rotatably mounted in the housing, the rotor being provided with one or more knives, one or more cutting strips which cooperate with the knives, and one or more openings, located in the lower part of the housing, for removal of the comminuted refuse, wherein the knife or knives present towards the inner wall of the housing cylindrically bent outer surfaces and cutting edges which run from one or more tips, (which lie forward in the direction of rotation of the rotor) backwards towards the knife-backs which are used to provide the connection between the knives and the axle.

Details and advantages of the invention can be seen from the following description with reference to the accompanying schematic drawings of embodiments of the invention. Of these:

FIG. 1 shows schematically in vertical cross-section a first embodiment of the apparatus according to the invention,

FIG. 1a shows a partial section of a cutting knife with the outer surface radially placed back,

FIG. 1b shows a partial section of a cutting knife with the tips of the cutting edge placed bask,

FIG. 2 shows schematically the rotor in the equipment according to FIG. I seen in the direction of the arrow II, in which the spacing equipment surrounding the rotor axle is omitted in all cases,

FIGS. 3a 3e show schematically in projection various shapes of knives viewed in the direction of the arrow II in FIG. 1,

FIG. 4 shows schematically a vertical section through an apparatus with two rotors.

In FIG. 1, the numeral 1 denotes a housing with a feed hopper l in the upper half and a split out-fall opening 1". The housing 1 is closed at either end by end-plates 2 and 3 which are also used for the mounting of a rotatably mounted axle 4 of circular cross-section. The axle 4 is shownprovided with two knife-supports 5 disposed substantially diametrically opposite one another. These carry knives 6, with a cylindrical outer surface and, have reinforcing ribs 6 on their leading faces (reckoned in the direction of rotation of the axle 4). In an alternative construction, as will be described later, the axle 4 can have a polygonal cross-section to provide a plurality of flat surfaces to which the knifesupports are secured. Also, more than two knife-supports 5 can be provided for knives 6. The knife-supports 5 can also extend the full length of the axle inside the housing, i.e. can be the same length as the knife 6, or can be in the form of carrying elements for the fastening of the knives at certain points only, along the axle. The size of the pieces of refuse which can be cut up by the apparatus is determined by the diameter of the half-shells 7 which are mounted around the axle. The greater the diameter of these, the less deep can a piece of refuse, e.g. a tin can, drop; and so much the smaller pieces are accordingly separated. Alternatively, a hollow axle could be used and the half-shells 7 could possibly be dispensed with. On rotation in the direction indicated by the arrow, the cutting knives slide with their cutting edges in front, in turn past the firmly fixed cutting strips 8 and 9 so that a piece of refuse arriving at the cutting strip 8 is pierced and cut up. The cutpieces separated from the refuse pieces are pushed on by the separating knife inside the lower part of the housing. At the axial cutting strip 9 a similar piercing and cutting operation takes place, if the previously separated cut-pieces do not drop free through the opening 1" which lies parallel to the axis of rotation. As will be described later such a slit can alternatively be arranged to run radially of the lower portion of the housing. The residual pieces thus pushed around and possibly further comminuted then arrive again at the cutting strip 8, and thence again pass to the lower part of the housing, where, if it is sufficiently comminuted, it drops through the opening 1". Instead of a single outlet opening 1 alternatively several outlet slits can be provided; and instead of two cutting strips, more of these can be mounted in the lower part of the housing. Preferably a cutting strip can be mounted for every outlet slit. The lower part of the housing can be completely in the form of a grid in which the single slits are separated from eachother merely by narrow ribs. The axial cutting strips 9 protrude somewhat over the inner side of the housing, so that the separated pieces of refuse on further travel do not jam. In order that the cutting edges of the knives 6 and those of the cutting strips 8, 9 should during the cutting operation slip past each other easily and without gaps, with a shearing action, the cutting strips 8, 9 and/or the knives 6 are radially adjustable. It has been found advantageous to slightly hollow-grind the knives 6 on the outer side, so that in the cutting operation they merely lay their cutting edges along the front-side of the cutting strips. FIG. la shows the outer side of a cutting knife shaped in the described way. In this Figure, the contour of the outer side of the knife runs from behind a point in the rim of the cutting edge in increasing divergence from the contour of the cylinder 2. In this way a low value for the frictional resistance can be obtained, and the knives slip continuously past each other.

As can be seen from FIGS. 2 and 3a 3e, the cutting edges of the knives 6 do not lie parallel to the rotor axis, thus providing a chronologically staggered cutting operation. In order to work with a minimum power-rating, it is advantageous to perform the initial cutting of a piece of refuse by a wedge-shaped projecting part of the cutting knife 6, and the final separation by a part of the knife which lies further behind in respect of the progressive rotary movement of the rotor. FIG. 2 shows a cross-section of a rotor-axle 4 of the same form as in FIG. 1, with two knives 6 set in knife-supports 5 according to FIG. 3a, in which the cutting edges 6.1 and 6.2 are set back symmetrically in the direction of the mounting flanges 6.4. FIGS. 3b, 3c and 3d show other possibilities for the shape of the knife 6 represented schematically in projection. The knife-shapes shown are not the only ones possible. The knife edges lying according to FIG. 3e between the tip and the mounting flange can be provided with teeth or notches or with relief grinding, disposed along the whole length of the cutting edge on the right of line 1,, I or in groups, which permits a better grip on the refuse. As shown in FIG. 3e the tips of the cutting edge are placed back into the plane l -1 In FIGS. 3a 3d the arrows D on the right hand side of the Figures, show the direction of rotation. The cutting edges which run back from the tips 6.3 in the direction of the mounting flanges 6.4 are designated by 6.1. In FIG. 3b they are shown bent concave, and in FIG. 30 they have different lengths, and are set at different angles owing to the sideways displacement of the tip 6.3. In FIG. 3d a form of knife is used with two unequally projecting tips 6.3 and 6.3, so that from left to right there are four cutting edges, 6.1, 6.1, 6.1 and 6.1. In the arrangement of unsymmetrical knives for example those shown in FIGS. 30 and 3d, the possibility arises of alternate displacement of the tips 6.3 and 6.3. So that the knives 6 can run even at high loading against the cutting strips 8, 9 in a trouble-free manner, and especially to, prevent the tips 6.3 from knocking against the cutting edges of the cutting strips, the tips of the knives are preferably set back slightly towards the axis of rotation. The parts 6.1 of the cutting edges which during the rotation of the rotor follow the tips, then take over the cut along the cutting edge of the cutting strips, with a scissor-like action.

The stability of the cutting knife 6 is ensured by the reinforcing ribs 6' provided at the fillet 6.5 (FIG. 1). These are advantageously placed immediately behind the tips 6.3 or, as shown in FIG. 3 slightly offset from the tips 6.3. In order to increase the cutting capacity of the knives the cross-section of the ribs can be selected to provide forms (not shown) so that the front side, turned towards the piece of refuse being cut into, is somewhat narrower than the rear face, which is connected with the mounting flange 6.4.

The advantage of the knives with a symmetrically placed tips (as shown in FIGS. 3c and 3d), which are arranged on the axle 4 preferably in alternating tip displacements or alternating with symmetrically placed tips, e.g. as shown in FIGS. 3a and 3b, consists of the fact that the refuse can be gripped better by staggered piercing points and can be cut. This is especially appropriate if small containers drop in sideways in the charging shaft (feed hopper) 1' and hence cannot easily be gripped by knives with symmetrically placed tips.

FIG. 4 shows an alternative embodiment of an apparatus according to the present invention having two rotors 41 and 42, which, in the manner already described are rotatably mounted in the lower part of a housing 43. The rotors can either be driven singly, or from a common driving motor optionally with a reduction gear. A feed hopper 44 is again provided above the comminutenhousing 43.

The arrangement illustrated in FIG. 4, besides the arrangement of two rotors rotating in mutually opposite directions as shown by the arrows, also shows different forms of securing the knives to the rotor axle 45. This is formed for example in a section along the length of the knife as a quadrilateral in which two mutually opposed surfaces 46, 46 serve for the mounting of two knives 47. The latter are detachably secured on the axle 45 by means of the securing elements 49, which do not project up to the cylindrical outer surfaces 48. The bearing surface of the knife 47 on the axle 45 can provide a suitable profile for prevention of tangential displacement between the two components. It is to be understood that, by the choice of a polygonal cross-section for the axle, the mounting of a plurality of knives can be considerably facilitated. Thus for example on a triangular or hexagonal axle three knives can be arranged in mutual equiangular arrangement.

The arrangement according to FIG. 4 provides a single centrally placed cutting strip 50, which rests on and is screwed on to a support rib of the housing 43. This cutting strip is advantageously so shaped that after blunting of the (upward facing) cutting edges it can be renewed by simply turning, through 180 so that the edges of the bearing surface now point upwards. When these edges also wear, all four edges must be re-ground. The regulation of the cutting edges of the cutting strips in relation to the cutting edges of the knives can be accomplished by means of a simple lifting of the cuttingedge surfaces 52, which basically lie somewhat lower than the axis of rotation. Obviously this is also possible in an arrangement provided with several rotors, in a manner not shown, with cutting strips adjustably mounted in the housing for example as shown in FIG. 1.

At the lower end of the housing 43, radially directed openings 53 are present for the removal of the comminuted refuse. These openings are advantageously provided in a grid, which is connected in one piece with the housing 43, or is demountably secured thereto. The slit-forming openings 53 obviously can alternatively be arranged in a radial direction.

Since it is in practice unavoidable that occasionally uncuttable pieces for example massive pieces of steel get thrown in, the apparatus is desirably provided with an overload protection not shown and with a reversing switch, so that an object blocking the rotor or rotors can be removed.

In the two forms of the rotors according to FIGS. 1, 2

and 4 massive continuous axles are shown on which the knives 6 47 can be fastened directly or by means of a knife support 5 (FIGS. 1, 2) in which the axle in the vicinity of the knife ends is supported on both sides. The rotors can, however, alternatively be so formed (in manner not shown) that the axle is not continuous but is divided into two sections, wherein a mounting is arranged to each section, and each end turned towards the interior of the housing is provided with a flangesheet. Between the two mutually opposite flange-sheets a number of knives are secured so that the rotor in practice forms a stable unit. The function of the halfshells 7, which has already been exhaustively described with reference to FIG. 1, can be accomplished by a similarly shaped piece of tube arranged between the flange sheets, or by means of a sheet-metal insert whose breadth corresponds essentially to the diameter of an equivalent piece of tube.

I claim:

1. Apparatus for comminuting refuse, especially bulky refuse, comprising a housing, a feed hopper mounted on said housing, at least one rotor rotatably mounted on said housing, at least one knife on said rotor extending the entire length of said rotor, cutting strips mounted on said housing cooperating with said knife, said housing having atleast one opening in the lower part for the removal of the comminuted refuse, said knife having an even number of cutting edges extending-in various directions set at an acute angle in relation to the axis of said rotor so that the juxtaposed ends of two adjacent cutting edges meet at a point which, in the direction of rotation of the rotor is in advance of the plane that contains the ends of the knives and the axis of said rotor, and the outer surface of said knife is shaped cylindrically along the cutting edge at least in a marginal portion.

2. Apparatus as in claim 1, comprising a plurality of knives, wherein the cutting edges of all said knives have the same length and the points at which adjacent cutting edges meet each other are situated in a single plane perpendicular to the axis of said rotor.

3. Apparatus as in claim 1 wherein the cutting edges are not of identical length and are inclined toward the axis of said rotor under angles of various sizes.

4. Apparatus as in claim 3, comprising a plurality of knives, wherein the points at which adjacent cutting edges meet each other are located in a plurality of planes perpendicular to the axis of said rotor.

5. Apparatus as in claim 1 wherein the outer surface of said knife has a recess directly behind the cutting edge.

6. Apparatus as in claim 1 wherein the points in which adjacent cutting edges meet each other are situated closer to the axis of said rotor in the radial direction than the cylindrical area of the outer surface of said knife or knives.

7. Apparatus as in claim 1 wherein the cutting edges of said knives are serrated.

8. Apparatus as in claim 1 comprising two rotors rotatably mounted in said housing and rotating in opposite directions so that the refuse situated above said rotors is carried along between said rotors, a common cutting strip being associated with the knives of both 5 rotors. 

1. Apparatus for comminuting refuse, especially bulky refUse, comprising a housing, a feed hopper mounted on said housing, at least one rotor rotatably mounted on said housing, at least one knife on said rotor extending the entire length of said rotor, cutting strips mounted on said housing cooperating with said knife, said housing having at least one opening in the lower part for the removal of the comminuted refuse, said knife having an even number of cutting edges extending in various directions set at an acute angle in relation to the axis of said rotor so that the juxtaposed ends of two adjacent cutting edges meet at a point which, in the direction of rotation of the rotor is in advance of the plane that contains the ends of the knives and the axis of said rotor, and the outer surface of said knife is shaped cylindrically along the cutting edge at least in a marginal portion.
 2. Apparatus as in claim 1, comprising a plurality of knives, wherein the cutting edges of all said knives have the same length and the points at which adjacent cutting edges meet each other are situated in a single plane perpendicular to the axis of said rotor.
 3. Apparatus as in claim 1 wherein the cutting edges are not of identical length and are inclined toward the axis of said rotor under angles of various sizes.
 4. Apparatus as in claim 3, comprising a plurality of knives, wherein the points at which adjacent cutting edges meet each other are located in a plurality of planes perpendicular to the axis of said rotor.
 5. Apparatus as in claim 1 wherein the outer surface of said knife has a recess directly behind the cutting edge.
 6. Apparatus as in claim 1 wherein the points in which adjacent cutting edges meet each other are situated closer to the axis of said rotor in the radial direction than the cylindrical area of the outer surface of said knife or knives.
 7. Apparatus as in claim 1 wherein the cutting edges of said knives are serrated.
 8. Apparatus as in claim 1 comprising two rotors rotatably mounted in said housing and rotating in opposite directions so that the refuse situated above said rotors is carried along between said rotors, a common cutting strip being associated with the knives of both rotors. 